A series of studies are proposed to investigate age-related alterations in the outer retina of the Japanese quail, which is a relatively short-lived, highly visual species with a cone-rich retina. Baseline morphological data will be estabished with regard to the choriocapillaris, Bruch's membrane, retinal pigment epithelium, photoreceptors, and integrity of the posterior blood- retinal barrier, all of which may show substantial alterations with increasing age. A variety of experimental manipulations will include tests of the following hypothesis: (1) that the effects of a short-duration, moderate-to-high intensity light exposure will have differential effects in the outer retina depending upon age, pigmentation (melanin) of the retinal pigment epitheliam and lipofuscin/age pigmentatin levels of the pigment epithelial cells; (2) that the phagocytic capability or activity of the pigment epithelial cells will vary with age and light-exposure history, and that such effects may be differentially expressed in the central vs. peripheral retina and effect the cone vs. rod photoreceptor shedding processes differentailly; (3) that dietary manipulations which include vitamin-E deprived (-E) vs. vitamin-E deprived Vitamin-A enriched (-E+A) will have differential effects on the accumulatin of age-related pigments in the retinal pigment epithelial cells. Further, that vitamin-E enriched (+E) diet may provide a protective effect against potentially damaging light exposure. By experimentally uncoupling the normally occuring relationship between retinal pigment epithelial concentrations of age-related pigments, both the phagocytic potential and the effects of ligh-damage upon the pigment epithelium can be assessed in young vs. aged animals, Japanese quail should prove to be an excellent laboratory species for experimental studies of aging in the vertebrate retina, since its offers all of the major advantages of a short-lived, highly visual diurnal species, with a pigmented retina of the avascular type, characterized by a large proportion of cones as well as rod photoreceptors. The studies proposed should have major relevance for age-related changes that occur in the human macula, particularly those associated with senile macular disease which is one of leading causes of visual disability and blindness in people 65 years of age and older. At present, a major need exists for laboratory species with many of the characteristics seen in the human retina, but which age rapidly, as does the quail.